Ship propulsion



Feb. 22 1927.

G. O. WATSON SHIP PROPULSION Filed 001;. 50, 1923 Inventor:

@eorge 0. Wa Ztson,

His Attorngy Patented Feb; 22, 1927.

UNITED STATES 1,618,790 PATENT orr cn;

GECRGE O. WATSON, F RUGBY, ENGLAND, AISSIGNOR T0 GENERAL ELECTRIC CO! i PANY, A CORPORATION OF NEW YORK.'

sum rnorULsIoif.

Application filed October 39, 1923, Serial Kc. 621,879, and inGreat Britain Iaovember- 1c, 1922.

My invention relates to systems of elec-- g has for its object the provision of means I wheel is whereby the generator and propeller motor fields may be controlled in a simple, reliable and efiicient manner.

In systems of this character it is customary to provide a master controller arranged to regu ate the operation of a pilot motor mechanically coupled to reversi le potentiometer rheostats which gradually varies the generator exciting current from zero to a maximum in either direction. Accordin to my invention the rheostats for contro lin the generator fields each comprise a resistance connected to a row of contacts having two contact faces over which two switch contacts are operated in opposite directions b a pilot motor. This motor is coupled to th controller which cuts out the motorwhen the rheostats have reached a position correspondin to the setting of the controller lever. brakin circuit is automatically made when the pi ot motor is cut out whereby the motor becomes .a' braking generator and is quickly brought to rest. Ahand= rovidedfor manual operation in case of failure of the pilot motor. A control switch for operating a contactor through which currentis sup lied to the propeller motor and generator l lEtldS' is so interlocked with the master controller as to prevent its being opened when either, the controller lever or the controller segments are in run ning sition for the pilot motor and to lock tin controller drum and lever place when the switch-is open.

My invention will he better understood on reference to the following description when considered in connection with the accompanyin drawing and its scope will be pointed out y the appended claims.

Referring now to the drawing, Figs 1 1 shows a system in whichmy invention has been embodied, and Fig. 2 shows certain details of the connections between the controller lever contacts and the follow-np device. r 4

Fig. l shows a plurality of direct current e follow-up device of a master generators 1 connected in, series with and arranged to supply current to propeller motors 2. A master controller comprising an arm 3 and follow-up device 4 are provided for controlling the operation of the pilot motor 5 which is operatively associated with generator field rheostats 6 and motor rheostats 7 through shaft 8 and bevel gears 9' and 10. The pilot-motor 5 is also mechanically coupled to the follow-up device 4 through shaft 8, bevel ears 11 and 12, shaft 13, bevelgears 14 an 1'5, shaft 16, bevel gears "1'1 and 18, shaft 19 and worm 20. The follow-up device is arranged to disconnect the pilot motor 5 from its source of current when the rheostats 6 and 7 have reached a position corresponding to the setting of the controller arm {3&- A. handwheel 21 is provided for manualoperation of the rheostats 6 and 7 in case thB'PllOtJlIOtOE 5 should become inoperative.

,Each of the generator rheostats 6 is pro- .vide'd'with a iesistance '24: connected across to he driven from the shaft 8 through bevel gears 9 and 10. Contact bars 28 and 29 are connected to opposite terminals of the generator field windings-30. The arrangement of the bevel gears 9 and lll'on'the shaft 8 is such. that the two switch contacts 26'- and 27 move in opposite irections so that -volt e across the termina s of the generator he). s can he built upfrom zero in the center :position to a maximum at either of the extreme positions, the polarity depending on the direction in. which the contacts are moved. With this construction of rheostat a large ninnber of connecting leads between the contacts, and cross connections between opposite ends of the resistance are avoided, and the resistance is arrangedlin a single line of units behind the switch, connections being made direct from the-contacts to the resistanceterminals with a 'rninimum of crossing leads. 2 a

The rheostats 7 of the propeller motor field windings 31 are'so arranged that their resistance is normally short circuited until tion to insert resistance in the motor field .circuits for the purpose of va ing the motor field to compensate for a c an ein the number of generators operated an also to com nsate for heating of the motor field win 'ng.

The master controller comprises six disks 33 to 38 inclusive attached to and insulated from a shaft 39 which is driven by the pilot motor 5 as previously explained. These segments 33 to 38 are arranged to collect current from contact plates 40 to 48 inclusive carried by insulation disk 51 mounted to direction, current fromthe source 25 is supplied to'the pilot motor controlswitch operating coil 54 through conductor 55, disk 33, contact plates 45 and 42 which are interconnected through the contact fingers on the controller arm 3, disk 36, brake coil 56, contacts of overload relay 57 having shunt coil 64 and series coil 69 and conductor 58. Upon energization of the coil 54 the switch 59 is closed and the motor 5 is connected to the source 25 through conductor 60, switch .59, and conductors 61 and 55. The motor 5 is provided with oppositely wound field coils 62 and 63. With the connections just described the motor 5 is connected to the source 25 in series with the field coil 62 andis set in motion to operate the rheostats 6 and 7 as previously explained until the space between the contact plates 40 and 41 is brought into alinement with the contact fingers mounted on the controller arm '3 when the switch coil 54 will be disconnected from the source 25 and the switch 59 will be opened thereby disconnecting the motor 5 from the source 25. At the same time the coil 56is deenergized and the switch 62 which is biased to closed position is closed to connect the braking resistance 63 across the armature of the motor 5. Movement of the controller lever in a counterclockwise direction also connects the shunt coil 64 of the overload relay 57 to the source of current 25 through conductor 55, disk 33, contact plates 45 and 40 which are interconnected through the fingers on the lever 3, disks 34 and 35, contact lates .41 and 48 which are interconnected t rough fingers on the lever 3, contact plate 47 conductor 65, disk 38 and conductor 66. Movement of the lever 3 in a clockwise direction connects the motor 5 to the source 25 for rotation in the opposite direction. Under these conditions the switch operatin coil 67 is energized, the switch 68 is c osed, and the field winding'63 is connected in series with the motor armature. The connections through which these results are 7 brought about will be apparent from what has been said previously. While the brake coil 56 is illustrated as connected in series with the switch 0 rating coils 54 and 67 it may obviously e connected in parallel 7 with these coils if desired.

The handwheel 21 which is provided for manual operation of the rheostats 6 and 7, is arranged to be declutched when not in use. This is accomplished by simply pull- 8 ing the hand wheel 21 to the left and disengaging the miter gears 18 and 70;

A swltch 71 is provided for controlling energization of the operatin coil 72 of the two pole switch 73 througi which excit- 8 ing current is supplied from the source 25 to the rheostats 6 and 7. This switch comprises a lever 74 pivoted at 75 and provided-with a de ending portion 76 the enlarged end of w ich is arranged to cooperate with slots 78 and 79 in the flanged peripheries of disks 80 and 81 mounted on the shafts 82 and 39 respectively. By this interlocking arrangement disconnection of r the rheostats 6 and 7 from the source 25 9 when the arm 3 is in other than a position to disconnect the motor 5 from the source 25 is prevented. Conversely when the switch 71 is open the arm 3 cannot be operated to energize the motor 5. 1

The operatinglever 53 is provided with a stop 83 for preventing the operator from throwing this. lever from full ahead position to full astern position without first bringing the lever to rest in the illustrated 1 stop position. This stop comprises a pivoted portion having two levers projecting at right angles to the pivot and to each other as shown. A spring may be provided for retaining the stop in the position to which it 1 is moved. An interlock 84 arranged to be operated in response to movement of the governor of the prime mover may be provided if desired.

Assuming the generators 1 to be rotating 1 at a suitable speed and the connections to be as illustrated in the drawing, the ship may be started in the ahead direction from rest by moving the controller lever 53 in a counterclockwise direction to a position determined .by the speed desired, thus bringing the contact fingers mounted on the arm 3 into engagement with certain of the contact plates mounted on the insulation disk 51 as previously ex lained and establishing 1: connections where y the pilot motor 5 is set in motion to move the contact members 26 and 27 in o posite directions thereby increasing the v0 tage applied to the generator fields. Under these conditions the folv scribed above.

low-u device 4 is rotated in a counterclockwise irection until the contact fingers on controller arm 3 are brought intoalinement with the space between contact plates 40 and 41, thereby disconnecting the pilot motor'from its source of current at a motpr speed determined bythe settin of the con--' contact with the stop 83 provided for the purpose. of stopping the lever in aposition'- to stop the ship. If it is desired to acceler ate the ship in the opposite direction the stop 83 must be rotated to permit movement of the lever 53 past it -in a clockwise direction, thereby operating the rheostats 6 in a manner vto reverse the polarity of the generator field winding and increase the voltage impressed thereupon. In order to bring the s lip to rest from operation in the astern position I the controller lever 53 is moved into contact with "the stop 83, thereby causing the generator field voltage to be reduced to zero and ,the pilot motor circuit to be broken by'rotation of the follow-up device. Topermit further movement of the arm 3 in a counterclockwise direction the stop 83must again be rotated as previously described. The overload relay 57 is pro- .vided for the purpose of interrupting the pilot motor circuit in case of excessive load upon the generators'and serves to prevent further increase in-the generator field voltage until the generator load current has assumed a safe value, but does not prevent a. decrease in this voltage by movement of the arm 3 in the reverse direction.

. I have ex lained my invention by illustrating and describing a certain specific embodiment thereof, but it will-be readily understood by those skilled in the art that the invention may be embodied-win many other forms than thatshown and described. I, accordingly, do not wish tobe restricted to the particular form orconstruction disclosed herein by way of example for the purpose of setting forth my invention in accordance with the patent statutes. The terms of the up W ded claims are, therefore, not restricted to the but are intende recise structure disclosed d to cover all. changes and modifications within the spirit and scope of n invention.

7 at Iclaim' as new and desire to secure by Letters Patent of the United States, is,-

1. A system of electric ship propulsion -wherein current is supplied to a propeller motor from a. direct current, generator provided with a field rheostat arranged to be connected to a source of current for controlling its excitation and wherein energization of a pilot motor for operating said rheostat is controlled by a. master controller having manually operated means for starting and a follow-up device for stopping said pilot motor, comprising means -operable only when said master controller is in off position for disconnecting said rheostat from saidsource.

2. A system of electric ship propulsion wherein current is supplied to a propeller motor from-a'direct current generator provided with a field rheostat arranged to be connected across a source of current for controlling the excitation of said generator and wherein energization of a pilot motor for operating said rhcostat is controlled by a master controller having manually operated means for startin and a follow-up device for stopping said pi ot motor, comprising means operable only when said master controller is in ofl position for disconnecting said rheostat from said source, a brakin resistor, means operable in response to 'deenergization of said pilot motor for connecting: said braking resistor to said pilot motor, and manual means for operating said generator field rheostat when said pilot motor is inoperative.

3. An electric power system wherein current is supplied to a motor from a direct current generator and wherein means arranged to be connected to a source of current are provided for controlling the field currents of said motor and said generator, comprising means for operating said field current control means, a master controller comprising manually operated means for starting and followup means for stop ing said operating means, and means opera le only when said master'controller is in off position for disconnecting said field current control means from said source.

4. An electric ship wherein current is supp ied to a propeller motor from a generator provided with means for regulating its field excitation and where-p in means for operating said field regulating means is controlled by a master controller having means for actuating and a followup device for deenergizingsaid operat ng means, comprising a switc for controlling the operation ofsaid operating means, and interlocking means associated with said switch and saidmaster controller to prevent operation of said switch when said actuating means and follow-up device are in a position to cause energi'zation of said generator.

5. An electric ship ropulsion system wherein current is supp ied to a propeller motor from a generator provided with means for regulating its field excitation and wherein means for operating said field regulating means is controlled by a master controller having means for actuating and a follow-up device for deenergizing said operating ropulsion system i means, comprisin a. switch for controllin operation only when said starting means and the ener ization 0 said operating means, MIC follow-up device are in a position to cause opposite y disposed slotted members ardeenergization of the field of said generator. 1! ranged to rotate with said actuating means In' wltness whereof, I have hereunto set In 5 and said follow-up device r ective1y,'said hand this tenth day of October, 1923.

switch having a part arrange to cooperate with the slots in said members to permit its GEORGE O. WATSON. 

